Twitter has acquired blogging platform Posterous, and the latter’s engineers, product managers and other staff members will soon be joining the existing Twitter teams so they can “make Twitter even better”.

In what very much appears to be a talent acquisition, existing Posterous bloggers should seriously consider moving their content to another blogger platform as soon as possible. While Twitter have given assurances that Posterous Spaces will remain up and running without disruption for now, reading between the lines in the various statements that have been made it’s fairly obvious that these services will not continue indefinitely, certainly as they are now.

Today we are welcoming a very talented group from Posterous to Twitter. This team has built an innovative product that makes sharing across the web and mobile devices simple—a goal we share. Posterous engineers, product managers and others will join our teams working on several key initiatives that will make Twitter even better.

Posterous Spaces will remain up and running without disruption. We’ll give users ample notice if we make any changes to the service. For users who would like to back up their content or move to another service, we’ll share clear instructions for doing so in the coming weeks.

We’re always looking for talented people who have the passion and personality to join Twitter. Acquisitions have given us people and technology that have enabled us to more quickly build a better Twitter for you.

I’ve highlighted the key section in bold. Note the parts about giving “ample notice” about changes to the service, and how they’ll be providing instructions on moving your Posterous Spaces to another service “in the coming weeks”.

I think the very best that Posterous users can hope for is that Twitter strips Posterous down, leaving the service bare but functional. But why do that? Why acquire Posterous at all? It doesn’t really fit with Twitter’s functionality, at least as is.

And those speculating that this means Twitter is now going to increase the 140-character limit of tweets are completely wrong. That’s never going to happen. Why? Because then it’s no longer Twitter.

The opportunities in front of Twitter are exciting, and we couldn’t be happier about bringing our team’s expertise to a product that reaches hundreds of millions of users around the globe. Plus, the people at Twitter are genuinely nice folks who share our vision for making sharing simpler.

Notice that the rest of the Posterous announcement is virtually identical to Twitter’s – it’s all about “ample notice” and “weeks to come”. Posterous has also written an FAQ about the acquisition, and it’s just as ominous. Twitter has bought Posterous because their team are doing things with content sharing that Twitter likes and wants to adopt. That’s it. End of.

Bottom line: if I was a Posterous user, I’d be making immediate arrangements to move over to Tumblr or a self-hosted WordPress.